The present invention relates to a development apparatus for developing latent electrostatic images formed on a photoconductor by use of a liquid developer in an electrophotographic copying apparatus, and more particularly to a development apparatus for developing latent electrostatic images formed on a photoconductor by causing a liquid developer to impinge upon the surface of the photoconductor.
As a development apparatus for use with an electrophotographic copying apparatus, such a development apparatus comprising a liquid developer container and a liquid developer distributor is known, wherein a liquid developer is fed into the liquid developer distributer by a pump means from the liquid developer container, and the liquid developer is impinged against the surface of the photoconductor from an impingement outlet of the liquid developer distributor, so that a latent electrostatic image is developed by a direct impingement of the liquid developer against the photoconductor.
Conventionally, in such a development apparatus, the impingement outlet of the liquid developer distributor comprises a plurality of orifices formed in the axial direction of a latent electrostatic image bearing photoconductor drum, namely in the longitudinal direction of the liquid developer distributor, or with a space placed between the respective orifices, or a slit extending in the longitudinal direction of the liquid developer distributor. However, in such liquid developer distributor, since only one or two developer inlets for introducing the liquid developer into the liquid developer distributor are formed, as the developer becomes more distant from the inlets, the flow rate of the developer gradually decreases, so that a uniform distribution of the flow rate of the developer in the longitudinal direction of the liquid developer distributor cannot be obtained. Such an ununiform flow rate of the developer, if any, will bring about an ununiform concentration of the developer and accordingly an ununiform development. Furthermore, since the flow rate of the developer is comparatively high around the impingement outlets closely adjacent the developer inlets, there is a risk that an insufficient development is locally caused in an area where the developer is directly impinged on the surface of the photoconductor drum due to a washing action of the impinged liquid developer. In order to eliminate the above-mentioned shortcomings, namely, in order to improve the ununiform distribution of the flow rate of the liquid developer in some conventional development apparatus, there are disposed a buffer plate before the developer impingement outlet. However, in practice, it is difficult to improve the ununiform distribution of the flow rate of the developer by such a buffer plate, and there is a risk that the buffer plate damages some good characteristics of the developer impingement type development apparatus.
Furthermore, in order to improve the uneven distribution of the flow rate of the developer, it has been devised to dispose a developer buffer member between the developer inlets and the developer outlets of the developer distributor, and various buffer members have been devised to accomplish the above-mentioned object. Of the various buffer members, a net-buffer member is known as the most effective. As a matter of fact, by use of the net-buffer member, the flow rate of the developer from the developer impingement outlet can be made uniform, so that uneven development or locally insufficient development can be eliminated. However, since the meshes of the net are so small that the net is apt to be clogged while in use by the developer, and this results in the distribution of the liquid developer becoming uneven.